The phrase "historic speech" is correct and usable in written English.
It is commonly used to refer to a speech that has had a significant impact on history or that is widely remembered for its significance. Example: "Martin Luther King Jr.'s 'I Have a Dream' speech is considered a historic speech that inspired change in the Civil Rights Movement."
On Tuesday morning, Obama will deliver his historic speech to the Cuban people.
The play reaches its climax in the historic speech, the Checkers speech, with which he vindicated himself.
Tears were brushed away and spontaneous applause rippled through the room as she continued her historic speech.
Iraqi state television announced this morning that "an important and historic speech" by Saddam Hussein would soon be broadcast.
The President has made mistakes on this issue: it was a mistake not to follow his historic speech in Cairo, in 2009, with a trip to Jerusalem.
On Thursday, Pope Francis made an historic speech to US Congress, challenging it to act on climate change, poverty, immigration, gun control among other issues.
Macmillan, touring Africa, made a historic speech on the subject of human rights, black & white, making it clear that Britain & South Africa are divided in their opinions.
His remarks were made at the annual event at the Soldiers National Cemeteryy in Gettysburg, Pa., near the site where Lincoln made his historic speech.
In a historic speech, he admitted the government had mishandled its relations with the Kurds, saying their long-running grievances must be addressed through greater democracy, not repression.
-- Beyond the President's historic speech in Cairo, other reasons exist for the Prime Minister's remarks about the United States in the interview.
While not an historic speech, Mr. Joffe said, "it was the right speech at the right moment in the right tone at the right place".
